We propose to study the effect on pulmonary removal of 5-hydroxytryptamine and norepinephrine of hemorrhagic shock and monocrotaline pretereatment. Amines will be perfused through insolated lungs of animals pretreated with the alkaloid monocrotaline. In animals subjected to hemorrhagic shock, amine removal by lung will be measured by application of double indicator dilution techniques. Finally, detailed study of the metabolic fate of 5-hydroxytryptamine in lung will be undertaken by high pressure liquid chromatographic analysis of lung effluents.